It is proposed to continue investigations into the electrochemical and in some instances the enzymatic oxidation of a number of biologically significant purine bases, nucleosides, nucleotides and oligonucleotides. The electrochemical methodology to be employed will include linear and cyclic sweep voltammetry, large scale and thin-layer controlled potential electrolysis and coulometry, thin-layer spectroelectrochemistry, various potentiostatic techniques and other appropriate methods. The electrochemical techniques will be complemented by a range of spectral, kinetic and other analytical methods to allow the characterization and identification of intermediates and products formed as a result of the electrooxidation reactions. Of particular importance in characterizing and identifying intermediates will be a technique based on a combination of thin-layer spectroelectrochemistry to generate UV-absorbing intermediates. The intermediate(s) will then be trapped by rapid freezing of the solution, lyophilization and then analyzed by forming appropriate silylated derivatives followed by separation and analysis by gas chromatography-mass spectrometry. Products will be analyzed using a broad range of liquid and gas chromatography methods, gas chromatography-mass spectrometry and various other spectral techniques. It is anticipated that the spectral, kinetic and analytical techniques developed to follow the course of the electrochemical oxidation reactions will also be readily adapted to monitoring the course of enzyme-catalyzed oxidations of purines. The long range goal of this research is to develop a clear and fundamental understanding of the oxidation chemistry of naturally occurring purine derivatives using electrochemical techniques and to demonstrate, by the investigation of various enzyme-catalyzed oxidations, that the oxidation chemistry developed on the basis of electro-chemical studies can provide detailed and uniquely valuable insights into the biological reactions of these compounds.